Field of the Invention
The invention relates to a method for producing a plurality of measurement regions on a chip, wherein electrically contactable electrode pairs are structured on the chip in each of the measurement regions and wherein the measurement regions are formed by producing a compartmental structure which separates the measurement regions from one another.
Description of Related Art
Moreover, the invention relates to a chip having a plurality of electrically addressable measurement regions, wherein a compartmental structure which separates the measurement regions from one another is provided on the surface of the chip.
A chip of the kind described hereinbefore and a method of producing it is known, for example, from U.S. Patent Application Publication 2009/0131278 A1. The chip is a silicon-based chip on the surface of which are provided a plurality of electrode pairs by metalizing and structuring. These pairings are in a two-dimensional array, preferably a chessboard arrangement. The electrode arrangements consist of electrode strips meshing with one another which ensure that the two electrodes of the electrode arrangement are adjacent to one another over a long distance.
The measurement regions are provided for functionalizing with certain biologically active substances. These may be, for example, antibodies which react chemically to specific antigens, these chemical reactions being electrically detectable by means of the electrode arrangement. Functionalization is carried out by a so-called spotting process, in which each measurement region is acted upon by another, e.g., water-based solution. The molecules responsible for the functionalization on the corresponding measurement regions are thereby immobilized. It is crucially important that the different liquids in the individual measurement regions are not mixed with one another, to ensure that only one type of relevant molecules is present on each measurement region.
To prevent the liquids of adjacent spots from being mixed together, it is proposed according to from U.S. Patent Application Publication 2009/0131278 A1 that mechanical barriers in the form of small walls may be provided between the individual measurement regions. The surface of the chip is thus divided into different compartments of a box, so to speak, the liquids each being “poured” into one of these compartments during the spotting process. However, it should be taken into consideration that the compartments present on the chip surface are of an order of magnitude in the μm range. Therefore, the effect of the mechanical boundaries comes up against its limits. As a result of the surface tension of the solvent, such as water, it may happen that in spite of the mechanical boundaries the liquids of adjacent measurement regions combine and thus the relevant functional molecules are mixed together.